As The Washington Post’s Steve Hendrix wrote earlier, the tradition began in 1987 when Vietnam War vets angry over the continued absence of missing comrades organized a mass convergence on Washington. The motorcycle was a vehicle of protest.

“If we have 5,000 vans and pickups and cars come down to D.C., people are just going to say it’s a traffic jam,” one of the event’s organizers told The Post. “If we bring 5,000 motorcycles, they are there for a reason.”

Trump, whose support for veterans has become something of a political hot potato, declared his backing for the cause at the rally. “We’re with you 100 percent,” he said Sunday.

Donald Trump greets members of Bikers for Trump during the annual Rolling Thunder rally on May 29 in Washington. (Alex Wong/Getty Images)

Bikers in attendance seemed to see a kindred spirit in Trump, whose campaign has been marked by his tough-talking, brusque manner.

“He speaks what’s on his mind and means what he says,” a 43-year-old contractor from Tennessee told the New York Times. “And that’s what a biker does. That’s the way we are: We say what we think. If you like it, you like it. If you don’t, go the other way.”

This is hardly the first time bikers have mobilized in Trump’s favor. In recent months, reporters have noted the presence of muscle-bound, leather-clad bikers at Trump rallies across the country.

The phenomenon of biker gangs mixing with ultranationalism, of course, is not simply an American one. In fact, perhaps the most successful convergence of bikers and power politics can be found thousands of miles away in Russia, a putative adversary.

Vladimir Putin, then Russia’s premier, takes part in a 2011 motorbike festival held by the Night Wolves youth group in the Russian town of Novorossiysk. (Alexey Druzhinin/AFP/Getty Images)

President Vladimir Putin has for many years cultivated a muscular nationalism, beginning with his own bare-chested persona. Right-wing Russian nationalist biker gangs have flocked to Putin’s banner. Most famously, a hard-core group known as the Night Wolves has comported itself as Putin’s hog-riding vanguard.

The pro-Kremlin biker gang deployed members to Ukraine following the annexation of Crimea and conducted parades through cities occupied by pro-Russian separatists. It has also embarked on profoundly antagonistic bike tours of Eastern European countries that resent such gestures of Russian patriotism. The group’s long-haired leader, Alexander Zaldostanov, nicknamed “The Surgeon,” is on a sanctions list and is prohibited from entering the European Union.

As the Eastern Europe scholar Timothy Snyder observes, a coterie of Russian neo-fascists has cheered Trump’s political success, seeing in the Republican candidate’s tirades against globalization, immigration and ruling cosmopolitan elites a like-minded politician.

“The American elite is not even American,” Alexander Dugin, a far-right ideologue dubbed Putin’s Rasputin, wrote in a recent blogpost. “Thus, there is Donald Trump, who is tough, rough, says what he thinks, rude, emotional and, apparently, candid.”